1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/*=============================================================
**
** Source: helper.c
**
==============================================================*/
/*
**
** Purpose: This helper process sets up a several blocks of memory
** that should be unwritable from the parent process, then uses a file
** to tell its parent process where that memory is so it can attempt a
** WriteProcessMemory on it. When the parent process is done we check
** here that it was (properly) unable to change the contents of the
** memory.
*/
#include "commonconsts.h"
#include <palsuite.h>
struct allhandles_t
{
HANDLE hEvToHelper;
HANDLE hEvFromHelper;
char *valuesFileName;
};
/* function: wpmVerifyCant
*
* This is a general WriteProcessMemory testing function that sets up
* the RAM pointed to and tells the companion process on the other end
* of the handles in 'Comms' to attempt to alter 'lenDest' bytes at
* '*pDest'.
*
* However, the memory at pDest[0..lenDest] is expected to be unwritable by
* the companion process. The companion is expects this. This function
* verifies that no bytes were affected
*/
int wpmVerifyCant(struct allhandles_t Comms,
char * pDest, unsigned int lenDest,
unsigned int lenLegitDest,
DWORD dwExpectedErrorCode,
const char* storageDescription)
{
char *pCurr;
FILE *commsFile;
DWORD dwRet;
unsigned int lenSafe = min(lenDest, lenLegitDest);
PAL_TRY
{
memset(pDest, initialValue, lenSafe);
}
PAL_EXCEPT_EX (setup, EXCEPTION_EXECUTE_HANDLER)
{
Trace("WriteProcessMemory: bug in test values for '%s' (%p, %u, %u), "
"the initial memset threw an exception.\n",
storageDescription, pDest, lenDest, lenSafe);
}
PAL_ENDTRY;
/* tell the parent what RAM to attempt to adjust */
if(!(commsFile = fopen(Comms.valuesFileName, "w")))
{
Trace("WriteProcessMemory: fopen of '%S' failed (%u). \n",
Comms.valuesFileName, GetLastError());
return FALSE;
}
if (!fprintf(commsFile, "%u %u %u '%s'\n",
pDest, lenDest, dwExpectedErrorCode, storageDescription))
{
Trace("WriteProcessMemory: fprintf to '%S' failed (%u). \n",
Comms.valuesFileName, GetLastError());
return FALSE;
}
PEDANTIC1(fclose, (commsFile));
/* Tell the parent the data is ready for it to adjust */
PEDANTIC(ResetEvent, (Comms.hEvToHelper));
PEDANTIC(SetEvent, (Comms.hEvFromHelper));
dwRet = WaitForSingleObject(Comms.hEvToHelper, TIMEOUT);
if (dwRet != WAIT_OBJECT_0)
{
Trace("helper WaitForSingleObjectTest: WaitForSingleObject "
"failed (%u)\n", GetLastError());
return FALSE;
}
PAL_TRY
{
/* check the stuff (as much as we can) that should NOT have changed */
for (pCurr = pDest; pCurr < (pDest + lenSafe); pCurr++ )
{
if ( *pCurr != initialValue)
{
Trace("When testing '%s': real memory values preservation failed "
"at %u offset %u. Found '%c' instead of '%c'\n.",
storageDescription, pDest, pCurr - pDest,
*pCurr, initialValue);
return FALSE;
}
}
}
PAL_EXCEPT_EX (testing, EXCEPTION_EXECUTE_HANDLER)
{
Trace("WriteProcessMemory: bug in test values for '%s' (%p, %u, %u), "
"the verification pass threw an exception.\n",
storageDescription, pDest, lenDest, lenSafe);
}
PAL_ENDTRY;
return TRUE;
}
int __cdecl main(int argc, char *argv[])
{
BOOL success = TRUE; /* assume success */
struct allhandles_t Comms = {0,0,0} ;
SYSTEM_INFO sysinfo;
char* Memory;
if(0 != (PAL_Initialize(argc, argv)))
{
return FAIL;
}
/* hook up with the events created by the parent */
Comms.hEvToHelper = OpenEventW(EVENT_ALL_ACCESS, 0, szcToHelperEvName);
if (!Comms.hEvToHelper)
{
Fail("WriteProcessMemory: OpenEvent of '%S' failed (%u). "
"(the event should already exist!)\n",
szcToHelperEvName, GetLastError());
success = FALSE;
goto EXIT;
}
Comms.hEvFromHelper = OpenEventW(EVENT_ALL_ACCESS, 0, szcFromHelperEvName);
if (!Comms.hEvToHelper)
{
Trace("WriteProcessMemory: OpenEvent of '%S' failed (%u). "
"(the event should already exist!)\n",
szcFromHelperEvName, GetLastError());
success = FALSE;
goto EXIT;
}
Comms.valuesFileName = argv[1];
/* test setup */
GetSystemInfo(&sysinfo);
{
unsigned int allocSize = sysinfo.dwPageSize * 2;
unsigned int writeLen = allocSize * 2;
/* First test: overrun the allocated memory */
Memory = (char*)VirtualAlloc(NULL, allocSize,
MEM_COMMIT, PAGE_READWRITE);
if(Memory == NULL)
{
Fail("ERROR: Attempted to commit two pages, but the "
" VirtualAlloc call failed. "
"GetLastError() returned %u.\n",GetLastError());
}
success &= wpmVerifyCant(Comms, Memory, writeLen, allocSize,
ERROR_INVALID_ADDRESS,
"should not write beyond committed allocation");
PEDANTIC1(VirtualFree, (Memory, allocSize,
MEM_DECOMMIT | MEM_RELEASE));
}
{
/* Allocate the memory as readonly */
unsigned int allocSize = sysinfo.dwPageSize * 2;
unsigned int writeLen = allocSize;
Memory = (char*)VirtualAlloc(NULL, allocSize,
MEM_COMMIT, PAGE_READONLY);
if(Memory == NULL)
{
Fail("ERROR: Attempted to commit two pages readonly, but the "
" VirtualAlloc call failed. "
"GetLastError() returned %u.\n",GetLastError());
}
success &= wpmVerifyCant(Comms, Memory, writeLen, 0,
ERROR_NOACCESS,
"should not write in READONLY allocation");
PEDANTIC1(VirtualFree, (Memory, allocSize,
MEM_DECOMMIT | MEM_RELEASE));
}
{
/* attempt to write to memory that is not committed yet */
unsigned int allocSize = sysinfo.dwPageSize * 2;
unsigned int writeLen = allocSize;
Memory = (char*)VirtualAlloc(NULL, allocSize,
MEM_RESERVE, PAGE_NOACCESS);
if(Memory == NULL)
{
Fail("ERROR: Attempted to reserve two pages, but the "
" VirtualAlloc call failed. "
"GetLastError() returned %u.\n",GetLastError());
}
success &= wpmVerifyCant(Comms, Memory, writeLen, 0,
ERROR_INVALID_ADDRESS,
"should not write in memory that is"
" RESERVED but not COMMITTED");
PEDANTIC1(VirtualFree, (Memory, allocSize, MEM_RELEASE));
}
EXIT:
/* Tell the parent that we are done */
if (!DeleteFile(Comms.valuesFileName))
{
Trace("helper: DeleteFile failed so parent (test1) is unlikely "
"to exit cleanly\n");
}
PEDANTIC(ResetEvent, (Comms.hEvToHelper));
if (!SetEvent(Comms.hEvFromHelper))
{
Trace("helper: SetEvent failed so parent (test1) is unlikely "
"to exit cleanly\n");
}
PEDANTIC(CloseHandle, (Comms.hEvToHelper));
PEDANTIC(CloseHandle, (Comms.hEvFromHelper));
if (!success)
{
Fail("");
}
PAL_Terminate();
return success ? PASS : FAIL;
}
|
